Video: Why the star witness in the case raised flags

This report first aired August 2009, and re-airs Dateline Friday, July 2, 2010. The full video will not be available online, but you can watch web-exclusive videos above.

Flint, Mich., where the steely Flint River winds through the heart of car country. Where on a beautiful spring day more than 20 years ago, one little boy mysteriously vanished.

How, why, whom?

Years passed, decades, the water kept its secrets. Memory faded and evidence disappeared, until all that was left was one mother's love, and her fragmented dreams of her child, calling her, haunting her, and pushing her to find the truth about what had happened to him.

When Christopher Alan Brown – who they called Alan – was born in November 1973, his mother Brenda Simpson could not have been happier.

When Alan was one, Brenda separated from his father, Jestine Brown – they later divorced. In 1978, she married an auto worker named Harvey who says he was smitten with her little boy.

Harvey Simpson: So, when I fell in love with her, I fell in love with him (chuckle). This was my son as much as it was hers. I mean I raised him; I helped to mold him into the little man that we had hoped he was going to become.

Alan excelled at school and sports. He loved Pacman, fishing and listening to "Through the Fire," by Chaka Khan.

Both Brenda and Harvey had good jobs on the assembly line at General Motors, Alan had one little brother, and another on the way.

Alan's father, Jestine Brown had also remarried – a woman named Rosalind Pettiford – and they had two little girls.

Hoda Kotb: In these sorts of blended families, where there's divorce, it's kind of complicated. Who gets to see the children, when?

Brenda Simpson: Well, I was going to have primary custody of Alan, and he had visitation.

Jestine's sister says Alan was close to his dad.

Ella Watson: He loved spending time with his father on the weekends or during school breaks.

But the relationship between Brenda and Alan’s stepmom was tense.

Ella Watson: They didn't like each other, didn't like each other at all. But Brenda would always let Allan come over to his dad's house and, you know, spend time with him. She would never keep him back from his dad.

In 1985, Alan was 11. When Easter rolled around, Brenda was surprised when he told her he did not want to spend the week at his father's as they had planned.

Brenda Simpson: But his dad kept calling him, and then he told him, "I'm going to take you camping and fishing."

Hoda Kotb: Those sound like the magic words for…

Brenda Simpson: They were the magic words. Yes, he packed up all his stuff. He was just happy, and he came over and he hugged me. He says, "I love you, Mom. I said, "I love you, too.

Hoda Kotb: And that's the last that you saw of him was that day.

Brenda Simpson: Yes.

That was Monday. On Friday, Brenda came home late and was alarmed to find her sisters waiting on her front porch.

Brenda Simpson: I rolled the window down and I was like, "What's wrong? I know something is wrong for them to be at my house at 11:00.”

Harvey Simpson: Her sister said Alan was missing. And it was like, "Well, how can that be? Missing from what? Missing how? He's supposed to be with his dad."

Brenda called Alan's father, demanding to know what had happened. He explained what he knew, that he and Alan had not yet gone fishing, and that while he was at work that day, his wife Rosalind was home with the kids. Rosalind said that at some point she bought McDonalds, put it in the kitchen, told the children to go in and eat, and left.

When she returned home a few hours later, Alan was missing. She looked for him around the neighborhood, and then called police.

Sgt. Francis Tull had almost no training as an investigator, but suddenly found himself in charge of a major case.

Sergeant Francis Tull: I get there and I start talking to the officers to find out what they had come up with.

Sgt. Tull's first thought was runaway or possible kidnapping and so the FBI was called in. Tull says they worked together. Every lead went nowhere.

Hoda Kotb: You probably put together a sort of profile of who is this child. Who was that boy in your mind's eye? Who was he?

Sergeant Francis Tull: A missing, scared little boy and that we needed to find him.

Days passed, with no sign of Alan. Frantic for help, Brenda did something she would do again and again in the years to come, she called the local newspaper. Flint Journal Cub reporter Jeff Smith was sent to her house.

Jeff Smith: You could just tell she was just drained, but determined, "I have to find my child."

This story was one of Jeff's first front page bylines, but it did not bring Brenda any closer to her son.

One week passed, and then another.

Hoda Kotb: You must have had a lot of conversations with God during these really difficult days. What were you asking for or praying for?

Brenda Simpson: I was praying to get my baby back, and I wanted him to be alive, but after about 17, 18 days…

Hoda Kotb: What were you praying for then?

Brenda Simpson: Then I prayed that the Lord would give me his body, so that I could bury him.

On April 30th, 18 days after Alan disappeared, Sgt. Tull's expanded his search efforts to include this peaceful bend in the Flint River three miles from Alan's father's home. By noon word came they'd found a body. Brenda's sad prayer had come true.

Sergeant Francis Tull: With the clothing description, deep down you knew.

Hoda Kotb: You knew.

Sergeant Francis Tull: You know, your heart starts sinking.

Reporter Jeff Smith raced to the scene.

Jeff Smith: You could see law enforcement people were out there with the tarp, or the body bag, it was just very quiet, very solemn.

Hoda Kotb: What did you lose that day?

Brenda Simpson: Oh, a big chunk out of my heart. I lost all my dreams that I had for him.

Brenda's grief was overwhelming but so were her questions. Alan was not the type of child to wander off. Why had he been at the river? How did he get there? Discovering his body was the beginning of a mystery she was just beginning to grasp.

Brenda Simpson: It didn't make sense. None of it made sense because he wouldn't have went out there without permission. None of this is adding up.

Part 2

11-year-old Alan Brown was buried on May 10, 1985.

Brenda Simpson: There was standing room only, at that church, all his little friends were there, and flowers.

It looked like a terrible accident. Alan couldn't swim; somehow he must have wandered over to the river and fallen in. A routine autopsy concluded the boy had died from accidental drowning. But that wasn't the end of it.

Brenda Simpson: They came to me and asked me did he drink? I said, "Drink?"

Hoda Kotb: They asked if he drank? He's 11-years-old.

Brenda Simpson: Right.

The question was asked because Alan's toxicology report came back with results that were highly unusual. His blood alcohol level was .15 – twice the level considered legally drunk for an adult – and there was a second reading, .07 for isopropyl or rubbing alcohol.

The investigator in charge of the case, Sgt. Francis Tull says he argued with the medical examiner to change Alan's cause of death to homicide, but the medical examiner refused.

Sergeant Francis Tull: He felt that a young boy got into the parent's liquor cabinet or got with some friends and they had some alcohol and was part of the drinking.

Despite that ruling, Tull says he and the FBI continued to investigate, starting with conversations with family members like Alan's step-mother Rosalind.

He was swamped with tips – most of them useless – and with reports from people saying they had seen Alan get into a car.

Sergeant Francis Tull: We had several vehicles – a white van, a green pickup truck – that people said they saw him get into.

Hoda Kotb: How did they describe the guy?

Sergeant Francis Tull: White male, you know, in his 30's.

That description matched a serial killer on the loose in nearby Detroit who forced young boys to drink alcohol, raped and then killed them. But Tull says he couldn't prove the man had been in Flint.

Hoda Kotb: So that's a dead end. Were you thinking it was a stranger?

Sergeant Francis Tull: I never ruled that out but my most focus was on – had to be – somebody he knew.

Meantime, Brenda was wrestling with her own suspicions and doubts. She had begun to wonder about Alan's resistance to visiting his father and step-mother Rosalind that day. What had she missed?

Hoda Kotb: What did he tell you about the visits?

Brenda Simpson: Well, most of the time he would talk about spending time with his dad. But, as he got older, he started acting a little different, a little strange.

Harvey Simpson: He would come in and he would be kind of down, a little depressed. We'd ask him, "What's wrong?" and he'd say, "Nothing." We used to call it the over-to-my-daddy’s-house syndrome. And it would pass, by the next day he'd be back to normal.

In her mind, Brenda replayed over and over Rosalind's story about what happened the day Alan disappeared.

Brenda Simpson: She said she went to McDonald's and got them some food. When she got back home, she was in a hurry to go to this job interview. So, she took the food in the house and came back out and told Alan to go in – he didn't go in.

For Brenda, the story just didn't make sense. Alan loved McDonald's, she said, and more importantly, she just couldn't believe he would have wandered three miles away to the river.

Sgt. Tull had little more than the reporter did – rumors, hunches, suspicions. He was very short on facts.

Sergeant Francis Tull: Other than the toxicology, showing the alcohol in his system. There was no evidence for anything.

Alan's case was in a kind of limbo, classified as an accident, and yet not officially closed.

Hoda Kotb: As the weeks and the months went on, and you're not getting a lot of traction, did it start moving back on the priority list?

Sergeant Francis Tull: I had no support from anybody on that particular case because it was ruled an accidental drowning.

Five months after Alan disappeared; Brenda gave birth to her third son. Her newborn did little to alleviate her sorrow. By now she was totally preoccupied with finding out what had happened to Alan, saving everything important to him in a small blue suitcase. She also began unannounced visits to the police.

Hoda Kotb: Every time you show up – two or three times a week, on the phone – what are they telling you?

Brenda Simpson: That they're investigating it.

What had once been holidays on Brenda's calendar were now rituals of mourning; Sad visits to Alan's grave on his birthday, and the anniversary of his death. Often, Brenda would play his music, take out his pictures, and cry.

Harvey Simpson: I didn't know how to chase that pain away that she was enduring. I didn't know what to do.

Four years after Alan's death the GM plant where Brenda worked closed. There was no new information on what had happened to Alan. Living in Flint had become painful.

Brenda Simpson: In my gut, I knew that whoever did this I had trusted my son with. Alan didn't go anywhere with strangers. I believe someone did something to him and I believed it was really, really close. I couldn't live here and not know who that person was.

The family packed up and moved to California; and there, Alan began to haunt Brenda in her dreams.

Brenda Simpson: It was like he was trying to give me a sign. I'd be saying, "Tell me what happened, tell me what happened," and just as he would get ready to tell me, I'd wake up.

Part 3

Hoda Kotb: Cases get cold, this one was ice cold. Did it ever resurface over the years or did it stay pretty much dormant?

Sergeant Francis Tull: For the most part it sat on the corner of my desk so I would never forget it.

Now living in California, Brenda Simpson periodically visited Flint. Usually around April 12 – the day her son Alan disappeared in 1985 – using the media to stir up publicity for Alan's case. She appeared on TV with lead investigator Sgt. Francis Tull around 1990.

Sgt. Francis Tull: What I'm hoping with this interview here that maybe someone that didn't want to talk 5 years ago, will decide to come forward.

Then again, by herself a few years later.

Jeff Smith had now been a reporter with the Flint Journal for nearly a decade.

Jeff Smith: She called me out of the blue.

Brenda had come to Flint to post fliers seeking information about her son.

Jeff Smith: I said, "Of course, I'll do something on that."I kind of thought that after all these years it was probably slim to no chance of them getting any new information. But there's no way I was going to tell a mother to give up hope of ever finding out what happened to their child. I can't do that.

Hoda Kotb: Were you always telling the truth when you said, "I'm trying?"

Sergeant Francis Tull: Yes, I never stopped trying.

Brenda didn't either, in part, she says because in her dreams, Alan would not let her rest.

Brenda Simpson: He never aged in the dream. He was still 11, just like he left that day. You know, it wasn't like he was in any pain. It was just that drive in the dream to keep pushing.

Brenda tried to focus on her 2 surviving sons, her husband and her job. Years passed, and her sons grew up and left home. The little boy in her dreams became harder to ignore.

Brenda Simpson: I knew what he was pushing me to do. He was pushing me to come back to Michigan.

And so, in 2002, 17 years after Alan's death, Brenda and Harvey moved back to Flint. Brenda retraced her well-worn path to Alan's grave. She quit work so she could concentrate full-time on finding out what happened to her son. She called Sgt. Tull and the police department.

Sgt. Tull says he gave Brenda all his phone numbers – work, cell and home – and always returned her calls, but Brenda still felt she wasn't being heard. She says she finally left him an angry voicemail.

Brenda Simpson: "I'm coming to put a tent up outside your door and no one else is coming in until you deal with me."

Brenda says that got his attention, and he finally called back. She asked him to bring Alan's case file to her house, including the autopsy photos, which she wanted to look at for the very first time.

Brenda Simpson: Got to see it in my mind. I've got to know that that's my child.

The photos were devastating, but Brenda found something else in the file that changed her mind about the entire investigation. This statement was taken from a woman claiming to have seen Alan's stepmother Rosalind and her brother forcing Alan to drink alcohol and sexually abusing him in the months before he died.

The woman also said she overheard them boast about forcing Alan to "walk the plank."

Walk the plank was the term that was used in the statement.

Hoda Kotb: That was sitting right there in file the whole time.

Brenda Simpson: Yes, ever since May of 1985.

Sgt Tull is the person who conducted the 1985 interview with that woman. When we asked him about it, he had only a vague recollection of the statement and the woman who had given it 20 years earlier.

Hoda Kotb: She comes to the station, gives you a statement basically saying that she saw Rosalind plying this kid with alcohol; did that set off alarm bells with you?

Sergeant Francis Tull: Absolutely, I don't remember a lot of that detail, but if that was the case there had to be more to it. We would have definitely focused on that.

Tull says he and the FBI followed up on a lot allegations at the time of Alan's death. None of them led anywhere, but Brenda couldn't believe that statement had sat untouched for all those years.

So, I tell him, "Well, what are we going to do?" I don't want him to know how upset I am.

Hoda Kotb: You're trying to be calm.

Brenda Simpson: I’m trying to be calm, because I know I've got to do something. So, he tells me, "Well, I'm going to take it back and have some more people look at it." I said, "Okay.”
Video: ‘There is no evidence he swallowed water’ (on this page)

By this time, Brenda was completely disillusioned with Tull and his efforts, but it no longer mattered. Tull retired, and the case was assigned to a new detective, who asked her to be patient. Soon, she says, he too was dodging her calls.

Jeff Smith: That really kind of shook her world, when she saw the notes. She just knew at that point that the police had really boggled the case, really dropped the ball there.

He wrote this article, published on the 19th anniversary of Alan's death, saying Brenda was threatening to "turn up the pressure on police" and to "start singing" about specifics of the case if authorities did not make headway soon.

The next day, 9 a.m. sharp, came a call from the police department, asking Brenda to come in to talk. And there she met the man who would become her hero.

Brenda Simpson: Jerry Parks.

Hoda Kotb: You smile when you say his name.

Brenda Simpson: He was a godsend. He was the first person that listened to me. It didn't take him very long to tell me that it was murder and that he would prove it.

Part 4

Nineteen years had passed by the time Detective Gerald Parks took over the investigation into the death of Alan Brown. Parks was retired, and worked as an advisor to the Flint Cold Case Squad for a dollar a month.

Hoda Kotb: Let's be clear, every month for all your work, you get paid one dollar? A month?

Det. Gerald Parks: Right. At the end of the year I get a little better than $11 because Uncle Sam's got to get his share.

Brenda says parks did something no one else had done – listened to her and included her in the investigation.

Brenda Simpson: He started piecing it together. He started calling me, asking me about people.

Det. Parks began by digging into the little blue suitcase Brenda had filled over the years with information about Alan.

Detective Gerald Parks: She had – amazingly – a lot of stuff that really helped us in our case.

Parks says right away he agreed this was no accidental drowning.

Det. Gerald Parks: You're about three miles from the river from the house. If you're going to go fishing, and you're a young 11-year-old boy, the first thing you’d take was your fishing pole – he didn’t.

Parks reviewed the case files. He constructed a timeline for the day Alan disappeared, starting with the moment his stepmom Rosalind picked him up at his aunt's house.

Det. Gerald Parks: He was with his aunt the day that he disappeared. We talked to the aunt.

Dateline also talked to Alan's aunt. She remembers quite clearly what happened when Rosalind picked him up that afternoon.

Ella Jean Watson: He was just crying and bawling his eyes out; he didn't want to go with her. It was like, she's hollering at him, forcing him to get into the car. I've never seen him act like that before. He was beating on the back of the window, screaming and hollering, "Aunt Jeannie, please don't let me go. Don't let me go." Eventually, they drove away.

Det. Gerald Parks: He had an intuition he was in trouble. He felt there something was wrong, that he wasn't liked, he wasn't wanted, and he had a fear.

Ella Watson: I blamed myself for a long time because I let him go. I could had have let him stayed, you know, maybe I don't know. You can't alter God's life.

Parks' interest in Rosalind increased. He studied the statements she had made in 1985, and brought her in for questioning. The story she told him now was very different from what she had said back then. Times changed, facts changed, very basic facts. In 1985, she said her mother was at work.

Audio tape: I went to get my mother from the Fisher Auto Body plant and picked her up at 2:42.

Detective Gerald Parks: You can't remember a lie. Try it, you can't remember a lie. You can remember things you do forever and ever because it's something you actually did, but when you try to remember a lie that's very difficult.

And then there was this — the statement from the woman claiming to have seen Rosalind and her brother Montel Pettiford force Alan to drink and sexually molest him in the months before his death.

When Parks tracked her down, she provided him with a bigger tip, saying a woman named Cathy who had been married to Montel may have actually seen whatever happened that day.

Hoda Kotb: One of the goals was to find whoever this Kathy person was.

Det. Gerald Parks: Well, that wasn't easy (chuckle) because Kathy had left the state and she wasn't easy to find.

Parks and his investigators finally found Cathy in North Carolina and interviewed her in the Fall of 2004. What she told them would be the first major crack in the case.

Audio tape: Yes. I was there.

For the first time, Cathy told what she had seen the day Alan disappeared. She was now divorced from Montel, but back in 1985, they were living here, at this house in Flint. Cathy said she was feeding her infant son when Montel and Rosalind came into the house, supporting Alan between them.

Audio tape: He was sick; they had to help him in the house.

Cathy said the two brought Alan into the spare bedroom. Next, Montel came into the kitchen, carrying a small brown bottle with skull and crossbones on it.

Audio tape: It seemed like he just opened the bottle and poured it in there.

What did he put it in, do you remember?

Kool-Aid.

She said Montel poured clear liquid from the bottle into grape Kool-Aid and also into eggs which were given to Christopher Alan.

Phone interview: He just poured it in.

So when he did this he went in and he had, did you see uh, Chris drink this?

Why had she kept this horrible secret all these years? Cathy said Montel frequently beat her and on that day, he held up the small bottle of poison and told her that if she told anyone, she and her baby would be next.

Parks called Rosalind back in, saying he now had an eyewitness implicating her in murder, and he threatened her with prison for life if she didn't start talking.

Audio tape, Rosalind: You know, I knew from day one I was going to get caught up in this.

Part 5

Audio tape, Rosalind: I did not do it.

Cop: I got an eyewitness.

Rosalind: They lying.

In November of 2004, Retired Detective Gerald Parks brought Rosalind Brown in yet again to discuss the death of her 11 year old stepson, Alan.

This time he had something he hadn't had before – incriminating eyewitness testimony placing her at the scene.

Audio tape, Rosalind: They are lying. I did not do that, none of that!

Audio tape, Cop: What choice do you have here? Going to prison for the rest of your life?

After more than 4 hours of interrogation, Rosalind admitted she and her brother Montel had taken Alan to the river that day, but she blamed Alan's death on her brother.

Audio tape, Rosalind: I took Montel to the river, he threw him, I didn't see him, I didn't poison him, I never touched the boy and I went home. Now you talk to Montel, he's going to say I did it. Go ahead I'll be your witness. I'll take your polygraph, whatever you want me to do. Can I please go now?

Hoda Kotb: From your perspective, after all of these years, all of your suspicions, all of your fight, you learn that your son was, in fact, poisoned, and it looks like your ex-husband's wife may be responsible.

Brenda Simpson: Right.

Hoda Kotb: To hear that, what did that feel like for you, finally?

Brenda Simpson: I was right all the time. That's what it felt like. Felt like I was right all the time.

Det. Parks now had the big break he needed; enough evidence to get court permission to exhume the little boy's body, to get a new autopsy, and to finally have Alan's death classified as a homicide. He took all of that to the District Attorney.

David Leyton, Genesse County Prosecutor: We think we know what happened. We think it was a homicide and we think we know who did it, but that's still not enough.

In May of 2005, stating there simply was not enough evidence for a conviction, the District Attorney declined to indict Rosalind Brown and her brother Montel.

Newscast: For the past 3 months, Simpson said she has waited hoping an arrest warrant would be issued, but late last week, she learned her dreams of closing the case once and for all would have to wait a little longer.

Brenda Simpson: I felt like somebody kicked me in my gut. I was so devastated. I got on the couch, and I laid there for about two days, hardly ate, I hardly drank anything.

Finally, after a couple a days, I got off the couch, and I said, "Pick yourself up, you have one more fight left in you." I told my husband, we go downtown, and I started the process of trying to get to the Attorney General's office. I'm not taking no for an answer.

Hoda Kotb: So if the D.A. tells you no, you go to the attorney general. There's someone else.

Brenda Simpson: Yes, we’ve got to find another door to kick open.

And behind that door was a young assistant attorney general, Oronde Patterson, who found 22 years of accumulated evidence now squarely in his lap.

Oronde Patterson: My first thought was, "It's not going to go anywhere. It's not going to result in any charges. Let me give an honest effort – go through the box, review it, write a memorandum stating why we couldn't do it."

The prosecutor had not counted on Brenda.

Oronde Patterson: Nothing in this world was just going to stop her from pursuing this. She was going to continue until she just couldn't breathe anymore. That was her son.

She called him weekly; sometimes daily. His updates gradually convinced her that he was taking Alan's case seriously. Soon she confided that her son was still haunting her in her dreams.

Brenda Simpson: He’s still coming. He's still coming.

Hoda Kotb: He's still saying the same kind of thing?

Brenda Simpson: Right, but I'm feeling like I'm on the right track.

In April of 2006, Brenda released 21 yellow balloons, one for each year Alan had been dead.

But Patterson wasn't sure he had enough evidence to prosecute. So much depended on eyewitness Cathy Pettiford, and ever since that day in 1985, she had been in and out of mental institutions. As a witness, she was less than ideal.

Oronde Patterson: I would just go over and over and over again what Kathy had to say. I wondered whether she was telling me the truth or whether she was making this up.

To see for himself, the prosecutor conducted a series of interviews with Cathy. As she would later say at a hearing, the day Alan disappeared, she saw Montel and Rosalind give him poisoned Kool-Aid and eggs, and then saw them come out of the bedroom with the boy – who she called Chris – in Montel’s arms.

Tape: Is Christopher conscious at that time?

Cathy, on tape: No.

Question: Is he saying anything?

Cathy: No.

Question: Is his body moving at all?

Cathy: No.

Cathy said Rosalind and Montel left, and when they returned, their shoes and pant-legs were muddy.

Testimony, question: Did either Montel or Rosalind say something to you?

The prosecutor decided that even with Cathy's history of mental illness, she would hold up on the stand. Her testimony was crucial.

Oronde Patterson: The scientific evidence helped her.

For Patterson and for Detective Parks, there was one last looming question: Why?

Hoda Kotb: To poison a little boy by pouring poison into the scrambled eggs seems so outrageous and preposterous that you wonder why someone would do that. What did you think is the motive here?

Detective Gerald Parks: Well there's a lot of jealousy, a lot of jealousy.

But both investigator Jerry Parks and prosecutor Oronde Patterson have another theory. They say it's possible that Alan had been sexually abused by Rosalind and Montel, and that he was about to tell his mother. If that's the case, they killed him not out of jealousy, but to protect themselves.

In May of 2007, Patterson charged Rosalind and Montel with first-degree murder. He says it was gratifying to give Brenda the news.

Oronde Patterson: She was very happy. I guess happy is an understatement as to how she felt.

Det. Gerald Parks: There was a lot of, "Yip, yip, and hurray." You know?

Brenda Simpson: I'm crying, it just seemed like, all a sudden, the trees are greener. The grass is greener, I knew they had the right people.

After 22 long years, Brenda Simpson was about to have her day in court.

Part 6

August of 2008, Brenda Simpson's decades-long battle for justice for her son Alan was nearing an end. Alan's step-mother Rosalind Brown and her brother Montel Pettiford were about to be tried for murder.

Brenda Simpson: It was just like 100 pounds was lifting off of me. I've been walking around with these two bricks, but I can't put them down. I’ve got to keep going, I got to keep going.

Prosecutor Oronde Patterson had lined up what he hoped was a strong case; a toxicology report showing alcohol in Alan's blood, an eyewitness, and Rosalind's own statement that she and Montel brought Alan to the river that day. He worried it wasn't enough.

Hoda Kotb: You had the emotions and the soul of a young boy's mother on your shoulders. Did you feel that?

Oronde Patterson: A tremendous amount of pressure. We could lose this case. So I was mindful of that from the very beginning.

Hoda Kotb: Just so I'm clear, you believe that Alan died of an accidental drowning?

Mark Latchana: Correct, she was an unlikely murder defendant. The majority of my clients are not women in their middle 50s. Meeting her, she talked about her grandkids and her kids, her career, and [her] husband.

Rosalind's lawyer set about debunking the toxicology report. He called in an expert who cited studies showing the alcohol in Alan's blood could have been created naturally – a normal by-product of a body decomposing in the water.

When it came to witness Cathy Pettiford, he questioned how anyone with her history of mental illness could accurately remember what happened one day 20 years earlier.

Mark Latchana: Poison out of a skull and crossbones bottle. I've never seen that in anything other than, you know, Bugs Bunny or the cartoons.

As for Rosalind's admission that she and Montel had been down to the water that day with Alan; her lawyer believed that was coerced by police.

Mark Latchana: That statement came at the end of about 4 1/2 hours of an interview with one detective. The statement was made after various different threats were made to her. Threats of, "spend the rest of your life in prison," threats to be prosecuted.

And the defense had one big advantage; motive.

In court, the prosecution never brought up any allegations of sexual abuse. Rosalind's lawyer argued there was no compelling reason for her to kill a little boy.

Hoda Kotb: Does your client have any history of violence? Is this true?

Mark Latchana: None, in fact, nobody, not one witness, had ever said that they saw her even spank this child.

Hoda Kotb: Oh, really?

Mark Latchana: And so, the closing argument was, "How do you get from not even disciplining him with physical punishment, to a plot to poison and murder him and put him in the river?" It just doesn't make sense.

Eight days of testimony, two days of jury deliberations. Then, for both of them, a one word verdict – guilty.

Brenda Simpson: It sounded good hearing it. I just broke down; I just broke down, a floodgate opened.

Harvey Simpson: You couldn't help but cry because you think, after all these years, after all this suffering, after all this pleading, we finally got the justice that Alan deserves.

The prosecutor was 13 when Alan died.

Hoda Kotb: Long time coming, wasn't it.

Oronde Patterson: Long, long time coming.

Alan's father, Jestine Brown, stayed married to Rosalind all those years, and attended court every day.

Reporter Jeff Smith – now in the insurance business – also attended the trial.

Jeff Smith: I kind of feel like the media really kept t it out there, and kind of put pressure on the court system to see this through.

In part, Brenda blames the original investigator, Sgt. Francis Tull, saying she would not have needed media pressure if he had done his job early on. Tull says he was hampered by the medical examiner’s finding that Alan's death was accidental, and says this case was always in his heart.

Hoda Kotb: If she were sitting in this seat instead of me, what would you say to her?

Sergeant Francis Tull: I'd tell her I was sorry, that I did not do this for her.

That is not something you hear every day. Sgt. Tull testified at the trial, and spoke to Brenda briefly afterwards.

Sergeant Francis Tull: She looked at me and said she was disappointed. And I said, "So was I," in myself.

Seargent Francis Tull: Well, it's the truth. When it's the truth, it's easier to say. I didn't solve the case for her. I should have focused on Rosalind more. I should have picked up that extra piece.

Brenda will never get the years back she spent fighting for Alan, but at long last, her crusade is over.

Hoda Kotb: Did you ever hear from Alan in your dreams after?

Brenda Simpson: No, I haven't dreamt about him. It's just like he's at peace now.

Time has finally washed away some of the pain caused on the banks of the Flint River, and one extraordinarily devoted mother has released the last balloon in memory of her son.

Hoda Kotb: I think nine out of ten women after 15, 16 years, probably would have stopped.

Brenda Simpson: I couldn't stop; I had to do it for Alan.

Hoda Kotb: What's in you?

Brenda Simpson: I loved him and I just didn't think he deserved to die like that. So, I had to fight for him; no one else could do it but me, no one else was going to care like I cared. No one was going to push like I was going to push. So, I just had to do it.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.